Drill

摘要

A drill comprising a first margin section, which is adjacent to the rear side in the direction of drill rotation of the chip discharge groove, and a second margin section, which is adjacent to the front side in the direction of drill rotation of the chip discharge groove, formed in a land section of the drilling end section; wherein a thinning section (140) is formed on the tip side of the inner wall surface of the chip discharge groove that is continuous with the inner peripheral edge of the cutting edge and extends to the land section.